The invention relates to a pneumatic weaving machine of the type in which the reed is composed of contoured lamellae which jointly delimit a guide channel for a transporting air flow, said channel being open at one side, namely the side facing the beating up line, said air flow being generated by a main blowing nozzle positioned at one end of the channel, and by a plurality of auxiliary blowing nozzles with their blowing apertures directed through the open side of the guide channel obliquely inward.
In pneumatic weaving machines of this type the angle between the axes of the transporting air jets delivered by the auxiliary blowing nozzles and the weft direction is chosen such that the transverse component of the force imparted by the transporting air jets to the thread to be transported is sufficient to keep the thread during the transport with certainty within the transport channel or, stated otherwise, is sufficiently large in order to prevent that the thread may leave the transport channel during the transport through the open side of that channel.
Experiments have shown that the angle of the transport jets issuing from the auxiliary blowing nozzles is not only important for the so called "transverse stability" of the thread in the transport channel but also influences other aspects of the thread behaviour during the transport phase.
It will be clear that an increase of the above indicated angle increases the chances of frictional contact of the thread with the "closed side" of the transport channel. Since this frictional contact is only disadvantageous for the average thread velocity which can be achieved, one has aimed at keeping said factor up till now as small as possible and therefore chosen the angle of the transport air jets not larger than was absolutely necessary in connection with the critical transverse stability.